Want a good gaming pc

HI ALL
I WANT a gaming pc but i dont wanna spend over 3k australian dollars I want a good video card like nvidia 6800 or radeon x800 whichever is cheaper and better im getting the Z-5500 5.1 speakers (logitech) and A good sound card wherether it be audigy or xfi xtreme music dont care. 19inch monitor and 1GB or more ram SO yeh any ideas on what i sould get cause im guessing all the stuff besides the monitor and speakers SHOULD I GET INTEL OR AMD INTEL DUAL CORE OR PENTIUM 4 which one just give me any recommandations. IM also getting the pc case made by nzxt called the NEMESIS ELITE in black or white whithout psu so i can GET a decent one ! LOL